1. Field of the Invention
The present invention relates to an endoscope system equipped with an endoscope and a laser probe that is inserted through an endoscope channel, and also to a control method for an endoscope system.
2. Description of the Related Art
Medical treatment is sometimes performed by inserting a treatment instrument through a channel provided in an endoscope, and causing a distal end of the treatment instrument to protrude from a distal end of the endoscope.
Since the aforementioned kind of treatment instrument is generally used in a state in which the distal end thereof has been caused to protrude from the distal end of an endoscope, it is desirable to check the protruding state thereof. Consequently, technology of various kinds has been proposed for detecting that a treatment instrument is protruding from the distal end of an endoscope.
For example, in Japanese Patent Application Laid-Open Publication No. 2002-125926, technology is disclosed in which the protrusion of a treatment instrument from the distal end of an endoscope is detected by a sensor such as a photo-interrupter. According to the technology described in the aforementioned publication, the detection result is used for controlling the magnification of an image.
Further, in Japanese Patent Application Laid-Open Publication No. 2008-212349, technology is disclosed that includes a forceps roller that is arranged in a proximal end portion of a forceps channel, a forceps encoder for detecting a rotation angle of the forceps roller, and a forceps detecting apparatus that detects the protrusion or retraction of a forceps from or into a distal end portion of the forceps channel based on rotation angle data from the forceps encoder. Further, according to the technology disclosed in the aforementioned publication, a detection result is used, for example, for an animated display of the protruding state of the forceps. In addition, in the aforementioned publication, technology is disclosed that, in a case where a detection result is that the forceps is not protruding, transitions to a stop mode to prohibit the passage of a high-frequency current to the treatment instrument.
In addition, in Japanese Patent Application Laid-Open Publication No. 2006-271871 technology is described that determines that a treatment instrument is positioned in the vicinity of a target site in a case where a signal of a predetermined luminance value or more is detected in a predetermined region within an observation field of view. According to the technology described in the aforementioned publication, a determination result is used as a trigger for starting video recording.
In this connection, in some treatment instruments a treatment portion for treating a subject by imparting energy to the subject is provided at the distal end of the treatment instrument. Examples of such treatment instruments include a laser probe that is described in the aforementioned Japanese Patent Application Laid-Open Publication No. 2002-125926, or a high-frequency treatment instrument that is described in the aforementioned Japanese Patent Application Laid-Open Publication No. 2002-125926 or Japanese Patent Application Laid-Open Publication No. 2008-212349. Surgery that pulverizes a stone by means of a laser beam in transurethral ureterolithotripsy may be mentioned as an example of treatment in which the laser probe of the former is utilized.